Rapid detection of mycobacteria such as Mycobacterium tuberculosis and Mycobacterium avium intracellulare is critical for providing appropriate early treatment and determining the need for patient isolation. In smear- negative specimens, mycobacteria can presently only be detected by culture, which generally requires a minimum of about seven days and often much longer. An attempt will be made to use PCR methodology for the rapid detection of mycobacteria, first in culture media after allowing a very brief period for bacterial growth, and then hopefully directly in patient specimens. Presently we are working on the methodology for obtaining sterile extracts of DNA from mycobacteria.